A quantitative evaluation of ten approaches to setting site‐specific cleanup objectives

Over the past several years, a number of reviews of various approaches employed or proposed by different jurisdictions for setting contaminated site cleanup objectives have been conducted. These methods are normally divided into two groups: absolute and relative. The absolute approach establishes a numerical concentration for a contaminant in soil that is applied to all sites, regardless of site‐specific factors. The relative approach generally employs a risk assessment modeling technique to derive a soil cleanup number based on site‐specific and chemical‐specific factors that will result in an acceptable exposure or risk. In the latter case, the numerical concentrations may vary from site to site, but the risk is the same. In the former, the numerical concentration is the same from site to site, but the risk, although unstated, varies. Numerous reviews of these methods have been undertaken, but all have been qualitative in nature, examining theoretical bases and not comparing the actual performance of each method in the assessment of one site. We have undertaken to derive cleanup guidelines for a single, existing contaminated site in Canada using ten different methods. Five of these were absolute methods (British Columbia Assessment Criteria, Alberta Soil Guidelines, Ontario Decommissioning Guidelines, Quebec ABC's, and New Jersey Acceptable Soil Contaminant Levels) and five were relative methods (U.S. Environmental Protection Agency Public Health Evaluation Manual, U.S. Army Primary Pollutant Limit Values, California Site Mitigation Decision Tree, California Technical Standard, and AERIS). The resulting analysis compares relative methods to absolute, examines the strengths and weaknesses of each approach, and discusses the similarities and differences of the outputs of the various approaches when employed to set cleanup objectives.     

Purification and Properties of γγ-Enolase from Pig Brain

Isoelectric focusing revealed three enolase isoforms in pig brain, which were designated as αα- (pI = 6.5), αγ- (pI = 5.6), and γγ-enolase (pI = 5.2). The pI of purified γγ-enolase was also 5.2. The γγ-enolase isoform of enolase was purified from pig brain by a purification protocol involving heating to 55°C for 3 min, acetone precipitation, ammonium sulfate precipitation (40%–80%), DEAE Sephadex ion-exchange chromatography (pH 6.2), and Sephadex G200 gel filtration. The final specific activity was 82 units/mg protein. As with other vertebrate enolases, γγ-enolase from pig proved to be a dimer with a native mass of 85 kDa and a subunit mass of 45 kDa. The pH optimum for the reaction in the glycolytic direction is 7.2. The K _m values for 2-PGA, PEP, and Mg²⁺ were determined to be 0.05, 0.25, and 0.50 mM, respectively, similar to K _m values of other vertebrate enolases. The amino acid composition of pig γγ-enolase, as determined by amino acid analysis, shows strong similarity to the compositions of γγ-enolases from rat, human, and mouse, as determined from their amino acid sequences. Despite the differences seen with some residues, and considering the ways that the compositions were obtained, it is assumed that pig γγ-enolase is more similar than the composition data would indicate. Moreover, it is likely that the sequences of pig γγ-enolase and the other γγ-enolases are almost identical. Li⁺ proved to be a noncompetitive inhibitor with either 2-PGA or Mg²⁺ as the variable substrate. This enolase crystallized in the monoclinic space group P2, or P2₁. An R _symm <5% was obtained for data between 50 and 3.65 Å, but was a disappointing 30% for data between 3.65 and 3.10 Å, indicating crystal disorder.     

Immunologic reactivity of purified human urinary kallikrein (urokallikrein) with antiserum directed against human pancreas.

Donkey antiserum to normal human pancreas absorbed with lyophilized human plasma recognized human urokallikrein in concentrated crude urine or after an approximately 500-fold purification. The urokallikrein antigen was associated with kinin-generating and alpha-N-p-tosyl-L-arginine methyl ester (TAMe) cleaving activity on isoelectric focusing, with the isoelectric point being 3.8 to 4.4. Both kiningenerating and esterolytic activity were removed from the purified urokallikrein by an immunoadsorbent prepared by coupling the IgG fraction of the absorbed donkey antiserum to Sepharose 6B. The failure of anti-plasma kallikrein to react in immunodiffusion with purified urokallikrein indicates that urinary kallikrein is distinct from plasma kallikrein although antigenically related to glandular kallikreins.     

Prostaglandin F levels in endometrial jet wash specimens during the normal human menstrual cycle.

The Gravlee endometrial jet wash technique has been used to collect uterine fluid in normal human volunteers for Prostaglandin F analysis throughout the human menstrual cycle. Uterine washings so obtained demonstrated a cyclicity in prostaglandin F content with low concentrations found during the proliferative phase and a 3-4 fold rise occurring during the secretory phase. Menstrual fluid prostaglandin F content collected with the jet wash technique gave the highest total concentrations.     

Reduction in apolipoprotein-mediated removal of cellular lipids by immortalization of human fibroblasts and its reversion by cAMP: lack of effect with Tangier disease cells.

High density lipoprotein (HDL) phospholipids and apolipoproteins remove cellular lipids by two distinct mechanisms, but their relative contribution to reverse cholesterol transport is unknown. Whereas phospholipid-mediated cholesterol efflux from cultured cells reflects the activity of the HDL receptor SR-BI, apolipoprotein-mediated lipid removal is regulated in response to changes in cellular cholesterol content (positive) and cell proliferation rates (negative). Here we show that immortalization of human skin fibroblast lines with the papillomavirus E6/E7 oncogenes increased their proliferation rates and selectively reduced the activity of the apolipoprotein-mediated lipid removal pathway. This reduction was accompanied by a decrease in cellular cAMP levels and was reversed by treatment with a cAMP analog. The stimulatory effect of cAMP was independent of changes in cellular phenotype or activities of cholesteryl ester cycle enzymes. The severely impaired apolipoprotein-mediated lipid removal pathway in Tangier disease fibroblasts, which persisted after immortalization, was not improved by treatment with a cAMP analog, implying that the cellular defect in Tangier disease is upstream from this cAMP-dependent signaling pathway.These results indicate that papillomavirus-induced immortalization of fibroblasts selectively reduces the activity of the apolipoprotein-mediated lipid removal pathway by a cAMP-dependent process, perhaps to prevent loss of cellular lipids needed for continual membrane synthesis.